Control valves are commonly used in process plants to control the flow of fluid (e.g., a gas, a liquid, etc.) or any other substance through pipes and/or vessels to which they are connected. A control valve is typically composed of one or more inlets and outlets and includes a flow control element or member (e.g., a valve gate, a piston, a valve plug, a closure member, etc.) that operates to control fluid flow through apertures that fluidly couple the inlet(s) to the outlet(s). A flow control element or member is typically coupled to a valve bonnet that is mechanically coupled (e.g., bolted, clamped, threaded into, etc.) to the valve body.
Typically, the flow control member moves within a cage and is configured to engage a sealing structure (e.g., a seat ring) that encompasses a flow path through the valve. To prevent fluid leakage between the cage and the flow control member, the flow control member is provided with a seal to sealingly engage a dynamic sealing surface of the cage. However, in practice, contaminates may enter the dynamic sealing surface. As a result, as the flow control member and, thus, the seal move within the cage, the interaction between the contaminates adjacent the dynamic sealing surface and the seal erode the seal, thereby decreasing the useful life of the seal and increasing the rate at which maintenance must be performed on the fluid valve.